Reservoir sensitivity can lead to the physical or chemical reactions to block the pore throat. It is helpful for reducing the damage on tight sandstone reservoir to study the reservoir sensitivity and its controlling factors. This paper mainly focuses on the tight sandstone of the Chang 4+5 and Chang 6 reservoirs of the Yanchang Formation in the Nanniwan Oilfield, Ordos Basin. The reservoir sensitivity characteristics were evaluated through the core sensitivity experiment after the petrological and petrophysical analysis and pore structure study. The influencing factors on tight sandstone reservoir sensitivity were discussed from several aspects, such as clay mineral composition, porosity, permeability, and pore structure. The results show that the rock type of the Chang 4+5 and Chang 6 reservoirs in the N 212 well block of the Nanniwan Oilfield is mainly arkose, with the mean porosity of 11.2% and 8.45% and the mean permeability of
0.35
×
10
−
3
μm2 and
0.44
×
10
−
3
μm2, respectively. The clay mineral components mainly include chlorite and illite/smectite. Both the two reservoirs are characterized by moderate to weak velocity sensitivity, moderate to weak water sensitivity, moderate to strong salt sensitivity, weak acid sensitivity, and moderate to weak alkali sensitivity. In specific, the Chang 4+5 reservoir is stronger in velocity and salt sensitivities, while it is weaker in water, acid, and alkali sensitivities than those of the Chang 6. The major controlling factors on reservoir sensitivity are clay mineral component, petrophysical property, and pore structure. Among these, the velocity sensitivity displays the positive correlation with pore structure, porosity, and permeability. The water sensitivity will become strong with the increase of the volume content of illite/smectite, but weak with the getting better of pore structure. The acid sensitivity is positively correlated with the volume content of chlorite but is negatively correlated with pore structure. With the getting better of pore structure, the salt sensitivity and alkali sensitivity will become strong and weak, respectively. The research results can be as the guidance for the tight sandstone reservoir protection in the study area and the adjustment and optimization of the regional reservoir development scheme.
Abstract. The use of furfural-acetone slurry as active diluents of Bisphenol-A epoxy resin (DGEBA) groutings has been studied by dynamic and non-isothermal DSC for the first time.Curing kinetics study was investigated by non-isothermal differential scanning calorimetries at different heating rates. Activation enery (E a ) was calculated based on Kissinger and Ozawa Methods, and the results showed that E a increased from 58.87 to 71.13KJ/mol after the diluents were added. The furfural-acetone epoxy matrix could cure completely at the theoretical curing temperature of 365.8K and the curing time of 139mins, which were determined by the kinetic model parameters.
Abstract. In this study, six types of commercially available ceramic tiles, including nano-structured ceramic tiles and regular ceramic tiles, were selected to investigate the effect of surface morphology on their stain-resistant property. The stainresistant efficiencies of various ceramic tiles with nano-size surface were measured in order to determine the appropriate method for testing ceramic tiles with nano-structure surface.
In order to investigate the damage aftereffect of energetic materials on diesel fuel tanks, this study compares the damage effects of three energetic materials, namely CuO/Al thermite, PTFE/Al+CuO/Al composite, and Zr powder, on diesel fuel tanks. The hole area on fuel tanks and the length and duration of diesel deflagration-formed fireballs are characterized, and the damage process and mechanism of armor piercing incendiary (API) projectiles are explored. According to the results, the CuO/Al thermite releases energy rapidly during projectile penetration into the target and exhibits the highest damage power. The hole produced by the thermite projectiles has an area twice as large as that produced by the composite projectiles, and the maximum fireball induced by the thermite persists twice as long as that induced by the composite. The rapid energy release of the CuO/Al thermite is primarily attributed to the vaporization of copper atoms into free copper at high temperatures, which further increases the pressure in fuel tanks. CuO/Al-filled API projectiles at a velocity of 950 m/s can produce violent deflagration and petaling damage to diesel fuel tanks.
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